Wholly aromatic polyester resins have long been known. For instance, 4-hydroxybenzoic acid homopolymer and copolymers have been provided in the past and are commercially available. Such polymers commonly are crystalline in nature, relatively high melting or possess a decomposition temperature which is below the melting point, and when molten frequently exhibit an isotropic melt phase. Molding techniques such as compression molding or sintering may be utilized with such materials. Representative publications which discuss these wholly aromatic polyesters include: (a) Polyesters of Hydroxybenzoic Acids, by Russell Gilkey and John R. Caldwell, J. of Applied Polymer Sci., Vol. II, Pages 198 to 202 (1959), (b) Polyarylates (Polyesters From Aromatic Dicarboxylic Acids and Bisphenols), by G. Bier, Polymer, Vol. 15, Pages 527 to 535 (Aug. 1974), (c) Aromatic Polyester Plastics, by S. G. Cottis, Modern Plastics, Pages 62 and 63 (July 1975), and (d) Poly(p-Oxybenzoyl Systems): Homopolymer for Coatings: Copolymers for Compression and Injection Molding, by Roger S. Storm and Steve G. Cottis, Coatings Plast. Preprint, Vol. 34, No. 1, Pages 194 to 197 (April 1974). See also, U.S. Pat. Nos. 3,036,990; 3,039,994; 3,169,121; 3,321,437; 3,553,167; 3,637,595; 3,651,014; 3,662,052; 3,668,300; 3,723,388; 3,759,870; 3,767,621; 3,773,858; 3,787,370; 3,790,528; 3,829,406; 3,857,814; 3,884,876; 3,890,256; 3,974,250; and 3,975,487; and U.K. Patent Application No. 2,058,102A.
In U.S. Pat. No. 3,637,595 a relatively high melting polymer is disclosed which may comprise 4-oxybenzoyl moiety, dioxyaryl moiety (e.g., p,p'-dioxybiphenylene), and terephthaloyl moiety.
It has been disclosed that certain polyesters may be formed which exhibit melt anisotropy. See, for instance, (a) Polyester X7G-A Self Reinforced Thermoplastic, by W. J. Jackson, Jr., H. F. Kuhfuss, and T. F. Gray, Jr., 30th Anniversary Technical Conference, 1975 Reinforced Plastics Composites Institute, The Society of the Plastics Industry, Inc., Section 17-D, Pages 1-4; (b) Belgian Patent Nos. 828,935 and 28,936; (c) Dutch Patent No. 7505551; (d) West German Nos. 520819, 2520820, 2722120, 2834535, 2834536 and 2834537; (e) Japanese Nos. 43-223; 2132-116; 3017-692; and 3021-293; (f) U.S. Pat. Nos. 3,991,013; 3,991,014; 4,057,597; 4,066,620; 4,067,852; 4,075,262; 4,083,829; 4,093,595; 4,118,372; 4,130,545; 4,130,702; 4,146,702; 4,153,779; 4,156,070; 4,159,365; 4,161,470; 4,169,933; 4,181,792; 4,183,895; 4,184,996; 4,188,476; 4,201,856; 4,219,461; 4,224,433; 4,226,970; 4,230,817; 4,232,143; 4,232,144; 4,238,598; 4,238,599; 4,238,600; 4,242,496; 4,245,082; 4,245,084; 4,247,514; 4,256,624; 4,265,802; 4,267,304; 4,269,965; 4,272,625; 4,279,803; 4,284,757; 4,285,852; 4,287,332; 4,294,955; 4,299,756; 4,311,824; 4,314,073; 4,318,841; 4,318,842; 4,332,759; 4,333,907; 4,335,232; 4,337,191; 4,339,375; 4,341,688; 4,346,208; 4,347,349; 4,351,917; 4,351,918; 4,355,132; 4,355,133; 4,355,134; 4,359,569; 4,360,658; 4,362,777; 4,370,466; 4,371,660; 4,374,288; 4,375,530; 4,473,682; 4,522,974; 4,684,712; and 4,746,694; (g) U.K. Application No. 2,002,404; (h) British Patent No. 1,568,541; and (i) European Patent Application Nos. 24,499, 45,499, and 92,843.
Representative disclosures of anisotropic melt-forming polyesters, poly(ester-amides), or poly(ester-carbonates) which may include 6-oxy-2-naphthoyl moiety are present in U.S. Pat. Nos. 4,161,470; 4,219,461; 4,256,624; 4,279,803; 4,299,756; 4,318,841; 4,318,842; 4,330,457; 4,337,190; 4,347,349; 4,351,917; 4,351,918; 4,355,133; 4,359,569; 4,362,777; 4,371,660; 4,375,530; 4,473,682; 4,522,974; 4,684,712; and 4,746,694.
In U.S. Pat. No. 4,219,461 a polyester is disclosed which comprises substantial concentrations of 6-oxy-2-naphthoyl and 4-oxybenzoyl moieties, and symmetrical dioxyaryl and symmetrical dicarboxyaryl moieties. The 6-oxy-2-naphthoyl moieties are provided in a concentration of approximately 20 to 40 mole percent in all instances. Also, while a 4,4'-dioxybiphenyl moiety is illustrated, no polymer is exemplified which incorporates this moiety. In the Example the polymer while in fiber form exhibited a substantially lower modulus than that commonly observed with the specifically defined polymer of the present invention.
In U.S. Pat. No. 4,299,756 a polyester is disclosed which comprises 6-oxy-2-naphthoyl moiety, 3-phenyl-4-oxybenzoyl or 2-phenyl-4-oxybenzoyl moiety, 1,3-dioxyphenylene moiety, and terephthaloyl moiety.
In U.S. Pat. No. 4,318,841 a polyester is disclosed which comprises 6-oxy-2-naphthoyl moiety, 4-oxybenzoyl moiety, the non-symmetrical 1,3-dioxyphenylene moiety, and terephthaloyl moiety.
In U.S. Pat. No. 4,370,466 a polyester is disclosed which comprises about 2.5 to 15 mole percent of 6-oxy-2-naphthoyl moiety, about 40 to 70 mole percent of 4-oxybenzoyl moiety, at least about 10 mole percent of 1,3-dioxyphenylene moiety, and at least 10 mole percent of isophthaloyl moiety. The polymer there reported while in fiber form is indicated to exhibit a substantially lower modulus than that commonly observed with the specifically defined polymer of the present invention.
In U.S. Pat. No. 4,473,682 a polyester is disclosed which comprises approximately 3 to 10 mole percent of 6-oxy-2-naphthoyl moiety, approximately 20 to 70 mole percent of 4-oxybenzoyl moiety, approximately 7.5 to 38.5 mole percent of 4,4'-dioxybiphenyl moiety, and approximately 7.5 to 38.5 mole percent of terephthaloyl moiety. The polyester of the present invention represents an improvement over such polyester. More specifically, the melting temperature of the polyester advantageously is decreased while surprisingly making possible the substantial maintenance of a highly attractive heat deflection temperature in molded articles formed from the same.
It is an object of the present invention to provide a novel melt-processable polyester which forms a highly tractable anisotropic melt phase.
It is an object of the present invention to provide a novel melt-processable polyester which forms an anisotropic melt phase and which has been found to be capable of melt extrusion to form quality high performance fibers, films, three-dimensional molded articles, etc. without the necessity to use a highly elevated melt-processing temperature.
It is an object of the present invention to provide a polyester which is capable of yielding quality fibers which exhibit a relatively high modulus.
It is an object of the present invention to provide a novel melt-processable polyester which forms a melt phase below approximately 375.degree. C. and which is capable of forming a molded article which exhibits a heat deflection temperature of at least 250.degree. C.
It is an object of the present invention to provide a novel melt-processable polyester which can be formed on a more economical basis than those disclosed in U.S. Pat. Nos. 4,219,461 and 4,473,682 since the more costly 6-oxy-2-naphthoyl and 4,4'-dioxybiphenyl moieties are present in lesser concentrations.
These and other objects, as well as the scope, nature and utilization of the invention will be apparent to those skilled in the art from the following detailed description.